Beckman Instruments, Inc.

Rosemount Analytical Inc.

Carl N Cederstrand

Dale F Warnke

Radhakrishna M Neti

Charles A Keenan

Hoke R Chism, Jr

Rolf W Siemon

Sharam M Salimian

The photometer of the present invention includes an optical system in which an emission beam generated by pulsed ultra violet radiation from a source is split into a sample beam and a reference interference beam by spectrally selective mirrors arranged in series. These mirrors reflect a beam having a wavelength range corresponding to an absorption wavelength of the gas to be detected onto one solid state detector and to pass a beam to a second spectrally selective mirror where a beam having second range of wave lengths corresponding to an interfering gas is reflected onto a second solid state detector. This second beam serves to measure the interfering gas and also as an imperfect reference channel. In a preferred embodiment the radiation from the source is split prior to entering the sample cell. One beam is directed through an optical path which avoids the sample cell but which is otherwise identical to the optical path described above, including series arranged spectrally selective mirrors to be further split the beam into two beams having wavelength ranges corresponding to the wavelength ranges of the sample and reference gases. These beams are directed to solid state detectors and the signals derived therefrom are combined with a second set of similar signals derived from the sample and reference beams which have passed through the sample cell.

Spectrophotometer and optical system therefor

An improved nondispersive infrared gas analyzer having at least one pneumatic or Luft-type detector and at least one black body type detector located one behind the other along the optical axis of the analyzer. In the preferred embodiment, a black body detector is exposed to radiation from a sample cell through an intervening pneumatic detector. The pneumatic detector absorbs radiation at specific infrared wavelengths, while the black body detector absorbs radiation substantially uniformly at all wavelengths. Signals from the pneumatic detector and the black body detector are combined electronically in an improved signal processing circuit to provide an output signal that is substantially free of the effects of disturbing influences such as infrared source intensity variations, mechanical vibrations and shock, and the presence of interfering compounds.

Infrared gas analyzer having detector elements of differing types

A method and apparatus is disclosed for selectively determining by non-dispersive infrared techniques the concentration of a gaseous constituent in a sample gas mixture while determining and discounting deleterious effects of spectrally interfering gases in the sample gas mixture.

Method and apparatus for negating measurement effects of interferent

A gas analyzer is disclosed which provides a dual channel capability for the simultaneous determination of the presence and concentration of two gases in a stream of sample gas and which has a single infrared source, a single sample cell, two infrared bandpass filters, and two infrared detectors. A separator between the filters and detectors prevents interchange of radiation between the filters. The separator is positioned by fitting it in a slot.

Split detector

A method of measuring trace level hydrogen chloride concentration in a gas stream is disclosed. The gas stream containing hydrogen chloride is passed through a heated vitreous carbon catalyst and then mixed with ozone in a point source reaction chamber. The light emitted in the chemical reaction is measured by a sensitive amplifier and the output is displayed on a meter, recorder, or any other suitable device. Apparatus for measuring trace level hydrogen chloride concentration in a gas stream is also disclosed.

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Brea, CA, United States of America

Carl N Cederstrand